R 3500 P/U 2WD V8-454 7.4L VIN W 4-bbl (1988)
Hydraulic Brake Booster: Testing and Inspection
Slow Brake Pedal Return
1.
Excessive seal friction in booster.
2.
Faulty spool action.
3.
Restriction in return line from booster to pump reservoir.
4.
Damaged input rod end.